ISO — sensitivity to light

Shutter Speed — how fast the diaphragm opens to expose the sensor to light

Aperture — the size of the diaphragm to allow light into the camera — smaller # is more light — f 1/1.8 = 0.5556 the size in inches of the

Metering Systems — What the camera uses to determine proper exposure  

  • Automatic Exposure — Standard feature on all digital cameras. Measures the amount of light in a frame and determines the best exposure
  • Center -Weighted Metering – Most common metering system found on digital cameras. Averages the exposure of a large area of the center-most portion of the frame with reads less away from the center. It is used mostly for general and portrait photography
  • Matrix (evaluative) metering — overall exposure is based on evaluating each zone individually and taking an average of the total light readings
  • Spot Metering — takes a reading only at the very center of the frame and disregards the rest. Use when a subject is back lit or has bright light upon it and the background is dark. It is also very useful for macro photography

Camera Exposure Controls

  • Not all cameras have the option of selecting the shutter speed and aperture; you may need to use the Program mode or automatic mode
    • Automatic — camera selects settings
    • Program Mode — chose portrait, sports or landscape settings
    • Aperture Priority — You choose small or large aperture openings, the rest is automated
    • Shutter Priority — is a semi-automatic exposure mode. You select the shutter speed and the camera automatically sets the aperture for a proper exposure
    • Manual Mode – -Select both shutter speed and aperture


ISO setting determines the sensitivity of your digital camera sensor to light. It also determines the amount of time an image needs to be properly exposed. (International


The lower the number, the more light is needed to properly expose the film/sensor

The higher the number, less light is needed. This is also called a “fast” iso because, in real terms, a high ISO can capture faster action in lower light.


Recommendation Settings (starting out)

200  — Bright Sunny day

400 — Overcast or Open Shade

800 — Indoors or night time


  • Not Enough Light!
  • When your digital camera’s light meter warns you there is not enough  light to correctly expose a scene, you could use a higher ISO
  • Set camera to ISO auto mode, your digital camera will automatically select a higher ISO
  • Or, Manually select the next higher ISO and see if the increased sensitivity allows you to obtain a correctly exposed picture. If it does, you can now take a correctly exposed picture without camera shake
  • You can safely hold a camera about 1/60th of a second without camera shake
  • Aperture Variable — Long or Shallow Depth of Field
    • Aperture is the diameter of the lens opening and is expressed as F-stop
    • Changing the aperture changes the depth (sharpness) in a scene from foreground to background. The smaller the aperture, the more of the scene will be sharp, but less light will reach the image sensor.
    • An aperture acts much like the pupil of an eye. The pupil opens wider as light decreases, letting in more of the available light. The pupil gets smaller when the amount of light increases in order to reduce the amount of light entering the eye
    • For landscape photograph you may want a smaller aperture for maximum depth of field so that everything from near foreground to distant background is sharp.
    • For a portrait, you will want a larger aperture to decrease the depth of field so that your subject’s face is sharp but the background is soft and out of focus


  • Using a Smaller aperture will give you longer depth of field
  • Assignment: 
    • Shoot at least 100 photos playing with your aperture settings
    • Bring 5 photo showing shallow depth of field (fuzzy background)
    • Bring 5 photo showing long depth of field (clear background)